Most in the national news media are talking about how Donald Trump is now the clear Republican frontrunner and will be nearly impossible to stop. They are only partially right.

Trump, who won South Carolina (and all of its delegates) with a little under one-third of the vote, certainly is the front-runner. He has won two of the first three contests and has a clear lead in delegates. He should do well on March 1, when many Southern states hold their primaries and more than 600 delegates are at stake. By definition, that makes him the front-runner.

But the Palmetto State primary results, combined with recent national polls, suggest that Trump remains a tentative front-runner, not some kind of unstoppable favorite.

Trump drew about 32.5 percent in South Carolina, a little less than the 35.3 percent he attracted in New Hampshire and about eight points more than the 24.3 percent he attracted in the Iowa caucuses.

In other words, he did not do as well as the primary winners did in New Hampshire or South Carolina in 2008 or 2012. That’s understandable considering the size of this year’s field, but it raises questions about the eventual breadth of his appeal.

Winning is good and losing is bad, but Trump’s problem is that while he has a high floor of support (many of his supporters will continue to back him no matter what he says or does), he may also have a low ceiling. We will find out if that is true over the next month, now that the GOP field has winnowed further.

Fox’s February 15-17 national survey found Trump at 36 percent on the ballot in the GOP’s national race and almost with a 2-1 lead over Ted Cruz, who was in second place. But when respondents were asked for a second choice, Marco Rubio and Cruz showed strong second-choice appeal. Trump did not.

That should not be surprising, given the controversy that Trump generates and his personal style.

It’s possible to win a primary with one-third of the vote, but it’s difficult to win a two-way or three-way race getting one in three voters. And that is a problem for Trump. His ceiling may prevent him from being the second choice of many Republicans.

The folks at CNN kept repeating on primary night that if another candidate had performed like Trump has so far, everyone would be saying that he is unstoppable. That’s true, of course. But the point is that Donald Trump definitely is not like any other candidate.

His language is not like a politician’s, and many of his positions are not classic Republican. That certainly enhances his appeal to some, but it disgusts and repels others, limiting his ability to attract significant additional support.

Most candidates who win multiple early contests have demonstrated broad appeal. In contrast, Trump remains a deeply polarizing candidate whose message obviously touches a certain kind of voter – one who is angry, wants a political revolution and is looking for a political strongman to mount a campaign against perceived enemies. That describes many, but not necessarily most, Republican voters.

The South Carolina exit poll found Trump doing very well among those voters who want a candidate who “tells it like it is” and well among those who want a candidate who “can bring needed change.” But he does very poorly among those respondents who want a candidate who “shares my values” and runs a weak second to Rubio among those who want a candidate who “can win in November.”

Even as he presses his argument that he is the only candidate who can stop Trump, Cruz’s showing in South Carolina has to be disappointing for him and his supporters. More than seven out of ten South Carolina GOP primary voters said that they were evangelicals, but Cruz carried only 26 percent of them. If Cruz can’t do well among those voters, he is in trouble.

Cruz did carry “very conservative” voters, another group at which he aims his message, but he must do better among evangelicals on Super Tuesday if he is going to remain a top tier hopeful for his party’s nomination. Once the primary process moves north and west, Cruz’s appeal wanes.

Jeb Bush’s exit from the race is a significant plus for Rubio, who after his South Carolina showing is now in a much better position to coalesce establishment support. That development is partially offset, of course, because John Kasich shows no sign of exiting the contest, thereby limiting Rubio’s ability to unite pragmatists.

As others have noted, the longer the establishment is divided, the more difficult it is to stop Trump from winning primaries and accumulating delegates.

Those who believe that Trump is unstoppable frequently note that no Republican who has won both New Hampshire and South Carolina has been denied the GOP’s nomination.

That’s true, but I believe that we have already established that the old “rules” do not apply, so I am not sure why anyone should regard two primary victories this year as an iron law of Republican politics.

None of this means that Trump can’t now win the nomination. But to do so, he will need to broaden his appeal – something that he has shown no inclination or ability to do, at least to this point.

But South Carolina’s results didn’t change Trump’s prospects in the Republican race very much. The outcome was more of the same, not an indication of his growing support in the party. Until that happens – and it could happen or never happen – the GOP nomination is very much up for grabs.

Ironically, Trump’s victory in the Palmetto State wasn’t the most significant development on Saturday. It wasn’t as important as Cruz’s disappointing showing or Bush’s exit from the race. Those two developments could alter the dynamics of a very unpredictable race. We will see whether they do.